package lession09;

import java.util.Scanner;

public class Demo05 {

	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int a,b=0,d=0,c=1;
		System.out.println("'");
		a=scan.nextInt();
		for (int i = 1; i <=a; i++) {
			for (int j = 1; j <=1; j++) {
				b=j;
			}
			c=b*c;
			d=d+c;
		}
		System.out.println(d);
	}
}
